This invention is concerned with a sanding device; more particularly, it is concerned with an in-line, hand held, sanding device.
Generally, in-line sanders are used as finishing sanders, the in-line motion thereof operates better with wood grain and more closely simulates hand sanding then the orbital motion of an orbital sander. Thus, the inline sander is used in place of hand sanding for large flat areas. There are examples in the prior art of dual motion sanders having the capability, selectively, to operate as an orbital sander, or as an in-line sander. These devices are generally bulky and heavy. There are, however, many devices disclosed in the prior art which are dedicated to in-line motion and to use as a finishing sander.
One such dedicated device is disclosed in the U.S. Pat. No. 2,830,411 of Hartman, which discloses an inline sanding device actuated by a rotary electric motor axially oriented normally to the sanding surfaces and driving a jack shaft through speed reduction gears, with the jack shaft supporting an eccentric for urging of the sanding surface in in-line reciprocation. Such an orientation of the electric motor created a bulky device; but the rotary electric motor provided a relatively quietly operating device.
The U.S. Pat. No. 2,545,942 of Crosby et al. discloses an orbital sanding device in which actuation is by a rotary electric motor axially oriented parallel to the sanding surface. The sanding surface is driven in an orbital path by eccentrics on shafts on either end of the motor shaft and at right angles thereto which are carefully counterweighted and connected to the motor shaft by bevel gears.
The U.S. Pat. Nos. 3,083,508; 2,790,276 of Fegley et al. and Acopian, respectively, disclose more compact linear sanding devices which are readily grasped and manipulated by one hand, but which are driven in linear reciprocation by vibratory electromagnets, and which can, therefore be, very noisy and distracting. A further problem encountered with the use of vibratory electromagnets is that any attempt to increase the speed of wood removal by bearing down on these devices will also increase the loading on the electromagnet and slow down operation thereof.
It is apparent that, ideally, what is required is a rotary motor actuated linear sander in a compact and economical construction which can be readily grasped and manipulated by one hand. In this fashion, the quiet operating characteristics of the electric motor and the power and durability inherent in such a device, might be accommodated in a package which is readily grasped by one hand to enable a relatively effortless sanding operation closely akin to hand sanding.